This was the plot of an urban novel. In the novel, the male protagonist saw a used condom in the place where the female protagonist lived and mistakenly thought that the female protagonist was using it, so there was a misunderstanding. Later, the male protagonist and the female protagonist realized their mistake and finally solved the problem. The plot of this novel, which usually involves emotions and misunderstandings, may reveal the weaknesses and contradictions of human nature, but it may also provide some enlightenment and thoughts.